Combination agitating means and spinning means with speed control means



Oct. 13, 1964 w. L. SONES ETAL 3,152,463

COMBINATION AGITATING MEANS AND SPINNING MEANS WITH SPEED CONTROL. MEANS3 Sheets-Sheet 1 Filed June 17, 1963 I NVENTORS lA/lLL/HN L. 5o/v6sJAMES 0. LL/arr Gaoee: r9. HEY/{0055 2s ATTORNEY Oct. 13, 1964 W. L.SONES ETAL COMBINATION AGITATING MEANS AND SPINNING MEANS WITH SPEEDCONTROL MEANS Filed June 17, 1965 3 Sheets-Sheet 2 Pawn 19. ,2 .MURCE v-GEAR 6'0MPUTOR 50x LOAD 1a i I 24 kg SPEED SPt'E'D nonm SENS/N6 TIMERPROGRAMMER MEANS #1 9 W J\| N i j' y! INVENTORS MA A mm L. 50/7615 JAMES0. 624/077" soeae 6'. /Y6'YHO(/56 A)! ATTORNE Y Oct. 13, 1964 w L. SONESETAL 3,

COMBINATION AGI TATING MEANS AND SPINNING MEANS WITH SPEED CONTROL.MEANS Filed June 17, 1963 5 SheetsSheet 3 //0 I I w can mural? I WINVENTORS M4 4mm 4. 50mg;

James O. ELL/arr 650/?65 A. A: fi/oase H16 ATTORNEY United States Patent3,152,463 COMBINATION AGITATING MEANS AND SPEN- NIN G MEANS WITH SPEEDCUNTRQL MEANS William L. Sones, James (I. Elliott, and George A.Neyhouse, Dayton, Ohio, assignors to General Motors Corporation,Detroit, Mich, a corporation of Delaware Filedllunc 17, 1963, Ser. No.288,336 7 Claims. (Cl. 68-42) This invention relates to a domesticappliance and more particularly to a control system for selectivelyvarying the cleaning action of first and second operative parts of aclothes washer in order to vary the clothes cleaning capability thereof.

Many cleaning devicesinclude a plurality of actuatable portions thatserve to move a cleaning fluid into intimate contact with soiled fabricso that a cleaning agent in the fluid will remove the soil'therefrom.For example, certain clothes washers have a spin tub with an agitator orpulsator located centrally thereof for oscilatory move ment relativethereto. In such devices the agitator will cause washing fluid to surgethrough fabric in the spin tub to provide the necessary cleaning actionand the spin tub serves to centrifuge the cleaning fluid from theclothes following a washing cycle. Recent developments in syntheticfabrics have resulted in a wide range of fabric types thatrequire agreater or lesser degree of washing action in order to remove the soiltherefrom. Furthermore, a typical user of a domestic washer having suchactuatable parts may desire to operate the machine in a manner tobalance the degree of washing action to optimize clothes wear andcleaning action.

It is, therefore, an object of the present invention to provide animproved control system for a clothes washer including means forrespectively controlling first and second actuatable means in order tooptimize the clothes cleaning action thereof while minimizing clotheswear.

A further object of the present invention is to provide an improvedcontrol system for a clothes washer of the type having a spin tub and anagitator or pulsator including improved means for infinitely varying thespeed of rotation of the spin tub and rate of pulsating of the agitatorwithin a predetermined range depending upon the type of fabric beingprocessed thereby.

A still further object of the present invention is to provide animproved control system for a clothes washer including first and secondmanually rotatable control knobs operatively associated with means forpreprogramming the speed of rotation of a spin tub and rate of pulsationof an agitator during washing and spin cycles of the clothes washer.

A still further object of the present invention is to provide improvedcontrol systems for a washer includinga drive motor speed controlcomputer operatively associated with a variable speed drive motor meansfor driving a spin tub and agitator of the washer by the provision ofmeans in association with the computer for providing in dependentinfinite speed control of the motor means while driving the spin tub andthe pulsator during washing and spin dry cycles of operation of themachine.

Further objects and advantages of the present invention will be apparentfrom the following description, reference being had to the accompanyingdrawings wherein a preferred embodiment of the present invention isclearly shown.

In the drawings:

FIGURE 1 is a schematic diagram of a prime movin system for a clotheswasher having a spin tub and an tator;

FIGURE 2 is a block circuit diagram of an electrical control systemincluding the present invention;

3,152,463 Patented Get. 13, 1964 FIGURE 3 is a more detailed circuitdiagram of the present invention; and

FIGURE 4 is a detailed circuit diagram of a computer control unitsuitable for use with the present invention,

In accordance with this invention and with reference to'FIGURE 2, ablock diagram is used to illustrate generally a clothes washer drivemotor 10 for driving a load 12 through a gear box 14-. The block diagramfurther includes speed sensing means 15 and a speed norm programmer unit16 that initiates signals which, in turn, can be used for controlling apower source 20 to the motor It) in accordance with the computations ofa computer control unit 18. The computer takes into account differencesin the size and orientation of loads such as clothes and water which canchange the torque requirements of the motor 10. In other words, outputspeed of the motor 10 is controlled basically in accordance with theloading thereof and the measurement of motor speed by the speed sensingmeans 15 can be used as one variable to signal deviations from a desiredperformance norm.

The speed sensing means 15 is provided with suitable mechanisms toconvert motor speed into electrical signals to be fed into the computercontrol unit 18. The computer or control unit 18 is preferably of thecompletely static type in that no moving parts other than the motoritself are employed in the operation thereof. Electrical circuitcomponents are included in the computer which are adapted to meter sixtycycle power to the motor lllfrom the power source 20 by varying theaverage voltage input to the motor to thereby effect a desired speedtherein. The system further includes a timer mechanism 24 thatcoordinates the system with a conventional washer cycle controlarrangement.

Suitable mechanisms are also provided in the speed norm programmer forvarying the desired performance norm of the operative parts of thelaundry device in a manner to be discussed.

The control system generally set forth in FIGURE 2 is illustrated asbeing incorporated in a clothes washer 22 somewhat schematically shownin FIGURE 1 as included an outer casing or shell 26 having a controlpanel 28 supportedon the upper portion thereof. The casing 26 isgenerally divided (into a machinery compartment 30 and a washing portionor water container chamber 32 formed by an upper cylindrical wallportion 34 of casing 26 having the upper end thereof opened at 35 andthebottom thereof closed by a bulkhead 36 having a vertically directedsleeve portion 37 sealed against leakage by an annular seal 39 at theupper end thereof for separating the Water compartment 32 from themachinery compartment 30. A spin tub 38 located within the watercontainer 32 has a top opening iii and a plurality of ports 42 in theupper portion thereof for allowing egress of water from the tub 38during high speed rotation thereof. The illustrative machine furtherincludes means for filling the tub 33 with water including a watersupply system having a hot water solenoid actuated valve 44'and a coldwater solenoid operated valve 46 manifolded into a mixed water supplyconduit 48 which terminates at a chute 5i) overlying the opening 40 inthe tub 38.

Within the tub 38 an agitator or pulsator 52 is mounted for oscillationto circulate or agitate the water contained in the tub 38. Thus, fabricplaced within the tub 38 is washed as the pulsator 52 causes the washingfluid and any included washing agent therein to surge back and forththrough the fabric. Following the washing cycle and spin cycle thelaundering fluid is drained from container 32 through a line (not shown)leading to the intake of a pump 54. I

The drive means for carrying out the Washing and spin cycle portions ofthe cleaning operation is representatively illustrated as including agear box 56 carried by a support bracket 58 suspended on a framework oflateral support arms 68 yieldably aflixed to the casing 26 by snubbers62. The upper part of the support bracket 58 serves as a stationaryshaft enclosing housing having bearings 64, 65 in the opposite endsthereof for journalling a spin shaft 68 directed upwardly of the gearbox 56 and having the upper end thereof secured to the bottom wall ofthe spin tub 38 by suitable fastening means such as bolts '70. The seal39 cooperates with the shaft housing to perform its sealing function.The spin shaft 68 is a tubular element and thereby serves as a supportfor an oscillating agitate shaft 72 directed upwardly from the gear case56 to be secured to the agitator or pulsator 52 at the upper end 74thereof. The drive motor 18 is representatively shown as being atwo-pole induction motor of the permanent start capacitor type that isoperatively interconnected in driving relationship with the gear box 56and the pump 54 by means of a suitable belt and pulley system 78. In theillustrated embodiment the motor and the pump 54 are secured by suitablebrackets 80, 82, respectively, to the gear box 56 and the lower portionof the suspended drive mechanism is pivotably connected in a resilientbushing 84 fixed to the bottom of the clothes washer casing for movementtransversely within the limits of the bulkhead sleeve 37 to an extentdependent upon the snubbing action of the snubbers 62. The resilientbushing 84- and snubbers 62 therefore serve to damp vibrations in thespin tub 38 during the operation thereof.

The drive motor It and gear box 56 and the water fill system for theillustrated clothes washer are electrically controlled and operated withother automatic portions of the machine by a conventional cyclicalcontroller including the timer 2d and a manually operated dial portion88 on the control panel 28 of the washer that operates a series ofswitches and through leads 88 controls the various elements in a desiredsequential order. The leads connect to the motor 18, solenoids 4-4, 46and the gear case 56 to condition the operative parts thereof to admitwater through the supply conduit 48, spin the tub 38 and oscillate thepulsator 52 therein in accordance with the desired cleaning operation.

The drive motor It) of the illustrated arrangement is further controlledby the transitorized computer control unit 18 which is basically of thetype illustrated in the copending application of Elliott at al., SerialNo. 159,014, filed December 13, 1961. The computer control unit 18 willsense and control the pulsate and spin speeds of the illustrated clotheswasher and will maintain them at a preselectable reference norm which,in accordance with certain of the principles of the present invention,is established by the speed norm programmer 16. As to the sensing andcontrolling of the spin speeds and the number of oscillatory strokes, asensor for motor speed is operatively associated with the motor 18 inposition to feed signals therefrom of the speed thereof into thecomputer control unit 18 to control the energization of the motor 10.The computer, as will be discussed, maintains the desired speed normreference of operation in the described washer throughout the operationthereof notwithstanding variations in the load powered thereby andvariations in the supply voltage to the motor. Thus, through all phasesof operation the speed control will be maintained at a desired normlimited only by the top speed of the motor itself.

It should be recognized that the position of knob 88 controls theoperation of the washer in a conventional fashion. In other words, cycleportions devoted to washing and spinning will be set up by the camactuated switches of the conventional cycle control and after the washercycle control calls for a particular function, the computer control unit18 and speed norm programmer 16 then come into play to regulate thedrive motor 10 in accordance with a preprogrammed or computerpermissible speed.

The computer control system of the invention is of the static,semiconductor type as best illustrated in FIGURE 4 and for purposes ofillustrating the present invention receives information from the speedsensing means 15, it being understood that other variable conditions canbe transformed into electrcal impulses or signals to be supplied to thecomputer control unit for varying the output signal therefrom such asspin tub unbalance, temperature, humidity, wash fluid clarity, and thelike. In general, motor speed variations produced by variable loading,line voltage and the like causes the computer control unit to affectlowering and raising of the motor voltage as required to maintain aconstant speed for operating the spin tub and pulsator in a desiredmanner.

In the illustrated arrangement, in order to control the rotative speedof the spin tub 38 and the pulsing strokes of the agitator 52, the speedsensing means 15 associated with the motor 10 includes a permanentmagnet pickup means similar to the type used in dynamometers whichcomprises a number of turns of wire 92 wound on a small magnet 94 asbest illustrated in FIGURES 3 and 4. The permanent magnet pickup 94 islocated in radial alignment adjacent to an outwardly toothed wheel means95 suitably journalled on a shaft 96 driven by a connection 98 to theshaft of the drive motor 10. The shaft of the drive motor 10 willreflect the number of oscillations of the pulsator 52 and also therotative speed of the spin shaft 38. As the toothed wheel means 95rotates, the permanent magnet 94 is subjected to varying air gaps andthe effective reluctance change causes flux changes in the magnet 84which induce a voltage in the coil 92. This voltage varies both infrequency and amplitude depending upon the speed of the wheel means 95and the correlative speed and pulsations of the devices associated indriven relationship therewith. The speed signal produced by the magneticpickup means is rectified or converted by a full-wave rectifier 1% andcapacitive filter units 102, 103 to allow the signal to be fed into thecomputer control unit 11.8.

In accordance with certain of the principles of the present inventionthe reference speed norm for a given programmed operation is controlledby improved means including a tub spin speed control knob 104 and apulsator stroke control knob 186 on the control panel 28 adjacent thecycle control knob 88. These knobs enable the rate of rotation of thespin tub and the strokes of the pulsator 52 to be selectively infinitelyvaried within a range limited by the maximum speed of the motor 10 and aminimum speed determined by design conditions such as motor heating.Such improved control of the clothes cleaning components of the aboveillustrated clothes washer adapts the device for automatic washing ofsubstantially all types of fabric since, during the washing cycle, thepulsator 52 can be regulated to have a very small number or a relativelyhigh number of oscillatory strokes depending upon the nature of thefabric to be cleaned and the degree of soil therein. By so controllingthe pulsator the user of the machine can select a particular type ofclothes washing action necessary to give adequate cleaning of the fabricwithout unduly increasing fabric wear because of the action of thepulsator thereon. Similarly, the provision of means for infinitelyvarying the speed of rotation of the spin tub 38 enables a user of themachine to select a speed that will effectively damp dry a particularfabric being processed by the machine.

Referring now to FIGURE 3, the clothes washer controller of the presentinvention is more detailedly set forth with the variable speed drivemotor 10 for oscillating the agitator 52 and spinning the tub 38 poweredfrom a l15-volt residential power source including a line 108electrically connected to motor 10 which is representatively illustratedas being of a permanent capacitor start type having a conductor 110electrically connecting it to one output terminal of the computercontrol unit 18 which has another output terminal thereof, in turn,connected to a second line 112 from the power source. The speed normprogrammer 16 more particularly comprises a plurality of cam actuatedswitches 114, 116, 118 operatively associated with a timer motor 120 ofthe timer mechanism 24 of the above-described clothes washer to beclosed thereby during certain phases of the operation of the washer tothereby program the controller for a particular drive motor speed. Whenthe clothes washer is energized the timer motor 120 will close a switch122 in the power line 112 to energize the speed control system of thewasher and following a predetermined'period of time required to fill thewasher with laundering fluid, the timer motor 120 Will operate theswitch 114 to program the control system for a desired number ofpulsator strokes desired by a particular user. In this case, once theswitch 114 is closed, a circuit is completed from one terminal of thewinding 92 through a conductor 124 through the closed switch 114, aconductor 126, and thence to a movable contact carrying arm 128 ofconductive material of a pulsator stroke control potentiometer 130 thatis moved relative to a variable resistance portion 132 of thepotentiometer 130 by rotating the pulsator stroke control knob 106 toinclude a greater or lesser portion of the resistance 132 in series witha conductor 134 electrically connecting the speed norm programmercircuit to a terminal of the input bridge 100. By virtue of the speednorm programmer circuit through pulsator stroke control potentiometer130 a user of the above-described clothes washer can modify the voltageinduced by the magnetic speed pickup arrangement to thereby control thevoltage input to the drive motor and hence the number of strokes of thepulsator during the agitate cycle of the washing operation.

The switch 116 is closed by the timer motor 120 during the spin cycle ofthe clothes washer to complete a circuit from conductor 124 through aconductor 136 having a resistance 138 therein and thence through acontact carrying arm 140 of a spin speed control potentiometer 142 thatis rotatable by means of the control knob 104 relative to a resistanceportion 144 of the potentiometer 142 in series with a conductor 146electrically connected to the conductor 134 and thence to the otherterminal of the bridge 100. The speed norm circuit completed when theswitch 116 is closed programs the computer 18 to maintain the rotativespeed of the spin tub 38 at a predetermined reference norm or speedwhich is made infinitely variable within the upper speed limit of themotor 10 by rotating the control knob 104 to include a greater or lesserportion of the resistance 144 in series with the magnetic coil 92 thatcarries the voltage induced by the magnetic speed pickup means.Depending upon the rotative position of the control knob 104, the signalproduced by the speed pickup arrangement that is fed into the computer18 can be varied to maintain the voltage input to the drive motor 10 soas to establish any desired rotative speed in the spin tub 38 during thespin cycle of operation of the clothes washer as produced by thepreselectable cyclical timer control knob 88.

Similarly, during the drain cycle of operation of the above-describedclothes washer, the timer motor 120 will close the switch 118 to includea resistance 148 in the input circuit to the controller to therebyprogram the clothes washer for a desired range of drive motor speedsrequired to operate the pump 54. Following the cleaning cycle a normallyclosed timer switch 149 is opened to deenergize the motor 120.

A calibrating potentiometer 150 is connected across the conductors 134and 124 for adjusting the input signal to the controller 18 whencalibrating the system.

The signal input from the magnetic speed pickup device 15, as modifiedby the speed norm programmer, is rectified by the bridge 100 and passestherefrom through the capacitive filter units 102, 103 which feeds theinput signal into the computer control unit 18 which is slightlymodified over the computer control unit of the above copendingapplication of Elliott et al. to meet the requirements of theabove-illustrated type of clothes washer. For purposes of thisspecification, the computer may be briefiy described as including aunijunction transistor 152 connected emitter 152e to base 152!) across acapacitor 153. The signal from the capacitive filters 162, 103 inresponse to variations in the input signal from the magnetic speedpickup as modifier by the speed norm programmer controls firing oftransistor 152 in combination with a control potential produced by abridge circuit 154 of diodes 156 that rectify the AC. power sourceacross lines 110, 112 to DC power with the voltage across the output ofbridge 154 being regulated by Zener diodes 158, 159 in conjunction withresistances 160, 162. Depending upon the imbalance between the controlpotential produced by the bridge 154 and the variable input signal fromthe bridge and capacitive filters 102, 103 the unijunction transistor152 fires to produce a motor control signal in the primary coil 162 of apulse transformer 164. Firing of the transistor 152 allows capacitor 153to discharge through a low impedance discharge path from the transistoremitter 152e, base 152]) and primary coil 162 to produce a voltage spiketherein. The resultant control signal or voltage spike passing throughthe primary side of the pulse transformer 164 serves as the intelligencefor operating a power supply switch to the motor 10 comprised of a pairof oppositely facing silicon controlled rectifiers 164, 166 which areactuated by a pulse signal in the secondary side of the transformer 164to be energized for a predetermined period of the full-wave form of thepower supply to produce a variable energization of the motor 10 andhence control the output speed thereof.

By virtue of the above-described control system, a user of theillusrated clothes washer can preselect the particular type of washingand spinning action that is desired for a particular type of fabric. Forexample, during the washing of a very delicate fabric, the user of themachine can manually rotate the pulsator stroke control knob 106 to alow-speed setting and also move the spin speed control knob 104 to adesired low-speed spin setting and then initiate machine operation bymeans of the machine cycle control knob 88. When the pulsator 52commences to oscillate relative to the spin tub 38 during the washingcycle of the machine operation, the onoif switch 122 is closed alongwith pulsator switch 114 and the current fiow through the input lines124, 134 to computer 18 is of a relatively large magnitude because ofthe fact that the contact carrying arm 128 of the pulsator strokepotentiometer is located relative to its variable resistance 132 so asto 'include only a small portion thereof in the circuit. This causes asubstantial imbalance between the signal input to the computer 18 andthe control potential from the bridge 154 and, accordingly, the SCRs164, 166 are controlled by the unijunction transistor 152 to fire onlyduring a relatively small portion of the full-wave form of the powersource across lines 108, 112. Accordingly, the motor 10 is de-energizeda substantial percentage of time and the speed thereof is reduced toprovide the desired washing action by the agitator as preselected by theuser. The spin speed of the drum 38 can be similarly controlled byrotating the spin speed control knob 104 to vary the amount ofresistance in the speed norm programmer circuit.

While the improved control arrangement is illustrated in conjunctionwith a washer machine having a spin tub and an oscillating pulsator, itwill be appreciated that the system is capable of varying the mode ofoperation of any washing device having actuatable clothes cleaningelementsthat might beneficially be operated through an infinite range ofoperations to improve soil removal and fabric wear.

While the embodiment of the present invention as herein disclosedconstitutes a preferred form, it is to be understood that other formsmight be adopted.

What is claimed is as follows:

1. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means for actuating said agitating means and said spin tub meansincluding prime mover means, semiconductor switch means in power supplyrelationship with said prime mover means, means for deriving a controlvoltage responsive to the speed of said prime mover means, meansprocessing said control voltage for controlling conductivity of saidsemiconductor switch means to maintain said prime mover at apredetermined speed norm, and speed norm programmer means for infinitelyvarying said control voltage within predetermined limits to operate saidprime mover means at variable speeds for producing a desired agitatingmeans cleaning action and spin tub extraction during the operativecycles thereof.

2. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means for actuating said agitating means and said spin tub meansincluding prime mover means, semiconductor switch means in power supplyrelationship with said prime mover means, means for deriving a controlvoltage responsive to the speed of said prime mover means, meansprocessing said control voltage for controlling conductivity of saidsemiconductor switch means to maintain said prime mover at apredetermined speed norm, first control means for programming firstselectable modulation of said control voltage for maintaining said primemover means at a desired speed norm corresponding to a desired agitatormeans cleaning action, and second control means for programming a secondselectable modulation of said control voltage for maintaining said primemover means at a desired speed norm corresponding to a desired spin tubextraction speed for producing a desired condition in the processedmaterial.

3. In combination, means for agitating material in the presence of acleaner, spin tub means for conditioning the material following apredetermined agitate cycle, means for actuating said agitating meansand said spin tub means including prime mover means, first and secondmanually actuatable control knobs, semi-conductor switch means in powersupply relationship with said prime mover means, means for deriving acontrol voltage responsive to the speed of said prime mover means, meansfor processing said control voltage for controlling the conductivity ofsaid semiconductor switch means to maintain said prime mover means at apredetermined speed norm, and means operatively associated with saidfirst and second manually actuatable control knobs for pre programmingthe speed of rotation of said spin tub and the rate of pulsation of saidagitator means by modulating the control voltage to produce a desiredoperative speed of said prime mover means during the agitate and spincycles of operation.

4. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means including prime mover means for actuating said agitating means andsaid spin tub means, semiconductor switch means in power supplyrelationship with said prime mover means, means for deriving a controlvoltage responsive to the speed of said prime mover means, means forprocessing said control voltage for controlling the conductivity of saidsemiconductor switch means to maintain said prime mover means at apredetermined speed norm irrespective of variations in the load driventhereby and fluctuations in the power supply thereto, first and secondmanually actuatable control knobs, first control means connected incircuit with said control voltage processing means for modulating saidcontrol voltage in a predetermined manner to produce a desired agitatormeans cleaning action, said first control means being actuated bymanually positioning said first actuatable control nkob, second controlmeans including means in circuit with said control voltage processingmeans for modulating said control voltage in a predetermined manner forproducing a desired spin tub extraction action, said second controlmeans being controlled by positioning said second control knob to apredetermined setting, and means for independently placing said firstand second control means in circuit with said control voltage processingmeans so that modulating action thereof will correspond to the agitateand spin cycles of operation.

5. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means including prime mover means for actuating said agitating means andsaid spin tub means, semiconductor switch means in power supplyrelationship with said prime mover means, means for deriving a controlvoltage responsive to the speed of said prime mover means, means forprocessing said control voltage for controlling the conductivity of saidsemiconductor switch means to maintain said prime mover means at apredetermined speed norm irrespective of variations in the load driventhereby and fluctuations in the power supply thereto, first and secondmanually actuatable control knobs, first control means connected incircuit with said control voltage processing means for modulating saidvariable control voltage in a predetermined manner to produce a desiredagitator means cleaning action, said first control means including meansfor infinitely varying said control voltage within first predeterminedlimits by manually positioning said first actuatable control knob,second control means including means in circiut with said controlvoltage processing means for modulating said control voltage in apredetermined manner for producing a desired spin tub extraction action,said second control means including means for infinitely varying saidcontrol voltage within second predetermined limits by positioning saidsecond control knob, and means for independently placing said first andsecond control means in circuit with said control voltage processingmeans so that modulating action thereof will correspond to the agitateand spin cycles of operation.

6. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means including a variable speed induction motor for actuating saidagitating means and said sp'm tub means, semiconductor switch means inpower supply relationship with said induction motor, means for derivinga control voltage responsive to the speed of said induction motor, meansfor processing said control voltage for controlling the conductivity ofsaid semiconductor switch means to maintain said induction motor at apredetermined speed norm irrespective of variations in the load driventhereby and fluctuations in the power supply thereto, and speed normprogrammer means for infinitely varying said control voltage withinpredetermined limits to operate said induction motor at desired speedsfor producing a desired agitating means cleaning action and spin tubextraction during the operative cycles thereof. 7

7. In combination, means for agitating material in the presence of acleaner, spin tub means for extracting the cleaner from the material,means including an induction motor for actuating said agitating meansand said spin tub means, semiconductor switch means in power supplyrelationship with said induction motor, means for deriving a controlvoltage responsive to the speed of said induction motor, means forprocessing said control voltage for controlling the conductivity of saidsemiconductor switch means to maintain said induction motor at apredetermined speed norm irrespective of variations in the load driventhereby and fluctuations in the power supply thereto, said controlvoltage deriving means including a magnetic type speed pickup includingmeans for varying the reluctance in a permanent magnet and a coil havinga variable voltage induced therein by the varying reluctance in saidpermanent magnet, said means for processing said control voltageincluding means for receiving said variable coil voltage and processingsaid variable coil voltage to produce an output signal for controllingthe conductivity of said semiconductor switch means, first and secondmanually actuatable means, first control means connected in circuit withsaid coil including means for modulating said variable control voltagein a first predetermined manner to produce a desired agitator meanscleaning action, said first control means being actuated by positioningsaid first manually actuatable means, second control means includingmeans in circuit with said coil for modulating said variable inducedvoltage therein in a second predetermined manner to vary theconductivity 1 $3 of said semiconductor switch means for producing adesired spin tub extraction action, said second control means beingcontrolled by positioning said second manually actuatable means, andmeans for independently placing said first and second control means incircuit with said magnetic speed pickup means so that modulating actionsthereof Will correspond to the agitate and spin cycles of operation.

References Cited in the file of this patent UNITED STATES PATENTS2,082,168 Hume June 1, 1937 3,018 649 Barbulesco et al. Jan. 30, 19623,049,654 Brucken Aug. 14, 1962

1. IN COMBINATION, MEANS FOR AGITATING MATERIAL IN THE PRESENCE OF ACLEANER, SPIN TUB MEANS FOR EXTRACTING THE CLEANER FROM THE MATERIAL,MEANS FOR ACTUATING SAID AGITATING MEANS AND SAID SPIN TUB MEANSINCLUDING PRIME MOVER MEANS, SEMICONDUCTOR SWITCH MEANS IN POWER SUPPLYRELATIONSHIP WITH SAID PRIME MOVER MEANS, MEANS FOR DERIVING A CONTROLVOLTAGE RESPONSIVE TO THE SPEED OF SAID PRIME MOVER MEANS, MEANSPROCESSING SAID CONTROL VOLTAGE FOR CONTROLLING CONDUCTIVITY OF SAIDSEMICONDUCTOR SWITCH MEANS TO MAINTAIN SAID PRIME MOVER AT A PREDE-